Final answer:
With the passage of Public Law 89-97 during the 1960s, Medicare and Medicaid were established, marking a significant expansion of the U.S. social safety net as part of the Great Society programs led by President Lyndon B. Johnson.
Step-by-step explanation:
Public Law 89-97 came into play with the passage of significant legislation during President Lyndon B. Johnson's administration in the 1960s. This law signified the establishment of Medicare and Medicaid, essential components of the social safety net in the United States.
Medicare provides health insurance to the elderly and some people with disabilities, while Medicaid offers medical assistance to individuals and families with low incomes. The establishment of these programs was part of a broader set of reforms known as the Great Society programs, which aimed to eliminate poverty and racial injustice.
The passage of Public Law 89-97 represents a key moment in the history of U.S. social policy, as it marked a significant expansion of the government's role in providing for the health and welfare of its citizens.